ISO 20602:2019

Ships and marine technology - Check valves for use in low temperature applications - Design and testing requirements

This document specifies requirements of design, manufacture, and test methods for cryogenic check valves to have excellent quality of leakage stability in very low temperature environments (−50 °C to −196 °C).

Navires et technologie maritime — Clapets de retenue destinés aux applications à basse température — Exigences de conception et d'essai

General Information

• Status: Published
• Publication Date: 06-May-2019
• ICS: 47.020.30 - Piping systems
• Technical Committee: ISO/TC 8/SC 3 - Piping and machinery
• Drafting Committee: ISO/TC 8/SC 3 - Piping and machinery
• Current Stage: 9060 - Close of review
• Completion Date: 02-Dec-2029

Relations

• Consolidated By: ISO 3175-5:2019 - Textiles - Professional care, drycleaning and wetcleaning of fabrics and garments - Part 5: Procedure for testing performance when cleaning and finishing using dibutoxymethane
• Effective Date: 06-Jun-2022
• Amended By: ISO 20602:2019/Amd 1:2021 - Ships and marine technology - Check valves for use in low temperature applications - Design and testing requirements - Amendment 1
• Effective Date: 18-Dec-2021

Overview

ISO 20602:2019 - Ships and marine technology - specifies design, manufacturing and testing requirements for cryogenic check valves intended for very low temperature environments (−50 °C to −196 °C). The standard targets valves used in marine and shipboard systems handling liquefied gases (e.g., LNG, natural gas, liquid nitrogen) and establishes requirements to ensure leakage stability and reliable operation under cryogenic conditions.

Key topics and technical requirements

• Scope and temperature range: Covers check valves for low-temperature service between −50 °C and −196 °C.
• Pressure–temperature rating: Defines working pressure and design-temperature considerations; valve class and maximum working pressure follow ASME B16.34 classing (manufacturers and purchasers can agree when class exceeds 900).
• Materials and components: Requirements for body, cover/bonnet, disc, seat, gaskets, hinges, bolts/nuts and their materials suitable for cryogenic service.
• Design features: Guidance on general check valve structures and selection of disc/seat types for reliable sealing at low temperatures.
• Manufacturing processes: Surface treatment, welding and heat treatment requirements to maintain material integrity in cryogenic conditions.
• Testing and inspection:
  • Material tests and non-destructive inspection (NDE) including radiographic testing (RT), penetrant testing (PT), and ultrasonic testing (UT).
  • Pressure tests, visual and dimensional inspections, heat treatment verification.
  • Cryogenic tests and fire safety tests where applicable; procedures and reporting requirements for test results.
• Marking and documentation: Identification and marking requirements to support traceability and compliance.
• Informative annex: Examples of cryogenic check valve designs.

Practical applications and users

ISO 20602:2019 is applicable to:

• Valve manufacturers designing and certifying cryogenic check valves for marine and offshore use.
• Shipbuilders, naval architects and offshore engineers specifying valves for LNG carriers, FPSOs, gas-fuelled ships and cryogenic piping systems.
• Classification societies, inspection bodies and purchasers requiring standardized acceptance criteria for leakage performance and testing.
• Maintenance and QA teams ensuring in-service valves meet cryogenic performance expectations.

Typical systems: LNG bunkering and transfer lines, cryogenic cargo piping, fuel gas supply systems on ships, and nitrogen systems.

Related standards

Standards referenced include ISO 28921-1, ASME B16.34, API 594, API 598, BS 6364, and relevant ASTM/ASME material and NDE standards. These provide complementary guidance on dimensions, testing methods and material specifications.

Keywords: ISO 20602:2019, cryogenic check valves, low temperature applications, ships and marine technology, design and testing requirements, LNG valves, leakage stability, pressure–temperature rating, non-destructive testing.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 20602
First edition
2019-05
Ships and marine technology — Check
valves for use in low temperature
applications — Design and testing
requirements
Navires et technologie maritime — Clapets de retenue destinés aux
applications à basse température — Exigences de conception et d'essai
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Pressure temperature rating . 3
4.1 Types of fluids . 3
4.2 Working pressure and designed temperature . 3
5 Design . 3
5.1 General structure of a check valve . 3
5.2 Materials — General . 3
5.3 Body . 4
5.3.1 Materials . 4
5.3.2 Manufacturing . 4
5.4 Cover (bonnet) . 5
5.4.1 Types . 5
5.4.2 Materials . 5
5.5 Disc . 5
5.5.1 Types . 5
5.5.2 Materials . 5
5.6 Gasket . 5
5.7 Valve Seat . 5
5.7.1 Types . 5
5.7.2 Materials . 6
5.8 Hinges and hinge pin (as applicable). 6
5.8.1 Types . 6
5.8.2 Materials . 6
5.9 Bolts and nuts . 6
5.9.1 Types . 6
5.9.2 Materials . 6
6 Surface treatment . 6
7 Welding and heat treatment . 6
7.1 Welding . 6
7.2 Heat treatment . 6
8 Test and inspection . 6
8.1 Material test . 7
8.2 Non-destructive inspection . 7
8.2.1 Radiographic testing (RT) . 7
8.2.2 Penetrant testing (PT) . 7
8.2.3 Ultrasonic testing (UT) . 8
8.2.4 Retest . 8
8.2.5 Reporting test result . 8
8.3 Dimension check . 8
8.4 Visual inspection . 8
8.5 Heat treatment inspection . 8
8.6 Pressure tests . 8
8.7 Fire safety test . 9
8.8 Cryogenic tests . 9
8.8.1 Test scope . 9
8.8.2 Test procedure . 9
8.8.3 Submission of test result .10
9 Marking .11
Annex A (informative) Cryogenic check valves — Examples .12
iv © ISO 2019 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 3, Piping and machinery.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
INTERNATIONAL STANDARD ISO 20602:2019(E)
Ships and marine technology — Check valves for use
in low temperature applications — Design and testing
requirements
1 Scope
This document specifies requirements of design, manufacture, and test methods for cryogenic check
valves to have excellent quality of leakage stability in very low temperature environments (−50 °C to
−196 °C).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5209, General purpose industrial valves — Marking
ISO 28921-1, Industrial valves — Isolating valves for low-temperature applications — Part 1: Design,
manufacturing and production testing
API 594, Check Valves: Flanged, Lug, Wafer, and Butt-welding
API 598:2016, Valve Inspection and Testing
API 6FA, Specification for Fire Test for Valves
ASME B16.5, Pipe Flanges and Flanged Fittings
ASME B16.10, Face-to-Face and End-to-End Dimensions of Valves
ASME B16.25, Buttwelding Ends
ASME B16.34:2017, Valves-Flanged, Threaded, and Welding End
ASME BPVC Sec. V, Nondestructive Examination
ASME BPVC Sec. VIII, Div.1:2018,Pressure Vessels
ASTM A182, Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged
Fittings, and Valves and Parts for High-Temperature Service
ASTM A194, Standard Specification for Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High
Pressure or High Temperature Service, or Both
ASTM A320, Standard Specification for Alloy-Steel and Stainless Steel Bolting for Low-Temperature Service
ASTM A351/A351M, Standard Specification for Castings, Austenitic, for Pressure-Containing Parts
ASTM E186/280/446, Standard Reference Radiographs for Heavy-Walled Steel Castings
BS 1868, Specification for steel check valves (flanged and butt-welding ends) for the petroleum,
petrochemical and allied industries
BS 6364, Specification for valves for cryogenic service
MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping Components
- Visual Method for Evaluation of Surface Irregularities
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at http: //www .iso .org/obp
3.1
nominal diameter
DN
alphanumeric designation of size for components of a pipework system, used for reference purposes
which comprises the letters DN followed by a dimensionless whole number that is related to the physical
size, in millimetres, of the bore or outside diameter of the end connections
Note 1 to entry: The number following the letters DN does not represent a measured value and shall not be used
for calculation purposes except where specified in the relevant standard.
Note 2 to entry: In those standards that use the DN designation system, any relationship between DN and
component dimensions shall be given, e.g. DN/OD or DN/ID.
[SOURCE: ISO 18139:2017, 3.1]
3.2
nominal pressure
PN
numerical designation relating to pressure that is a convenient round number for reference purposes
Note 1 to entry: It is intended that all equipment of the same nominal size (DN) designated by the same PN
number shall have the same mating dimensions appropriate to the type of end connections.
Note 2 to entry: The permissible working pressure depends upon materials, design and working temperature
and has to be selected from the pressure/temperature rating tables in corresponding standards.
[SOURCE: ISO 18139:2017, 3.2]
3.3
nominal pipe size
NPS
dimensionless number for the purpose of pipe, flange, or flanged fitting end connection size
identification
Note 1 to entry: The number is not necessarily the same as the flange or flanged fitting inside diameter.
[SOURCE: ISO 18139:2017, 3.3]
3.4
class
alphanumeric designation used for reference purposes related to a combination of mechanical and
dimensional characteristics of a component of a pipework system, which comprises the word “class”
followed by a dimensionless whole number
[SOURCE: ISO 18139:2017, 3.4]
2 © ISO 2019 – All rights reserved

4 Pressure temperature rating
4.1 Types of fluids
The types of fluids are shown in Table 1.
Table 1 — Types of fluids
Temperature
Type Liquid density (density)
(in atmospheric pressure)
LNG
−163 °C to −88 °C (434 kg to 478 kg/m )
(Liquefied natural gas)
NG
−160 °C to −65 °C (0,7 kg to 0,89 kg/ m )
(Natural gas)
LN2
−196 °C (804 kg/m )
(Liquefied
...